[Solved] Whats wrong with the c code?

A 2D array does not decay to a pointer to a pointer. By using:

  maxim=findMax((int **)a,m,n);

you are forcing the compiler to ignore your error.

Instead of

int findMax(int **a,int m,int n)

use

int findMax(int a[][20],int m,int n)

and then, call the function simply using:

  maxim=findMax(a,m,n);

You said:

The problem statement says that int findMax(int **a,int m,int n) has to be used.

In that case, you have cannot use a 2D array for a. You’ll have to use:

int main()
{
   // Define a to be an array of pointers.
   int* a[20];
   int m,n,i,j,maxim;

   scanf("%d",&m); //Rows

   // Make sure m not greater than 20. Otherwise, you'll end up
   // accessing memory out of bounds.
   if ( m > 20 )
   {
      // Deal with error.
   }

   scanf("%d",&n); //Cols

   for(i=0;i<m;i++)
   {
      a[i] = malloc(sizeof(int)*n);
      for(j=0;j<n;j++)
      {
         scanf("%d",&a[i][j]);
      }
   }

   maxim=findMax(a,m,n);
   printf("Max is %d\n",maxim);

   // Deallocate memory.
   for(i=0;i<m;i++)
   {
      free(a[i]);
   }

   return 0;
}